#7307319 Stepper: Added FlowProgress component to stepper

Changes proposed in this Pull Request

• Added a new component, FlowProgress, that shows information like “Step 2 of 10”.

Testing instructions

• If you want to show the FlowProgress in a step you should add a new prop to StepContainer:

...
const stepProgress = { flowLength: 10, currentStep: 4 };
...

<StepContainer
   ...
   stepProgress={ stepProgress }
   ...
/>

In this example the values are hard-coded, but the idea is to store this information in the ONBOARD_STORE, so it’s manageable from the flow configuration instead on the step (since the step may be used in different flows).
The store changes are on a different PR.

Related to #63355